Examination of normal intestine using confocal endomicroscopy

Endoscopy is an important clinical tool for the diagnosis and treatment of gastrointestinal disorders. However, biopsy tissue is still required in many cases to obtain a definitive histopathological diagnosis. The aim of this study was to evaluate confocal endomicroscopy (CEM) as a tool for conducting virtual biopsies of the colon by comparing CEM images with biopsy samples from normal colon.

The study cohort comprised 45 patients who underwent investigative colonoscopy between April 2004 and January 2006, 25 of whom also had biopsy due to suspected diseases such as inflammation and neoplasm. The small and large intestine were examined with CEM using an intravenous injection of fluorescein, and CEM images were compared with conventional histopathological results from biopsied samples. In addition, the injected fluorescein was localized immunohistochemically to further analyze the CEM images taken in vivo.

A total of 46 biopsies were taken, of which 24 demonstrated no histopathological abnormality and were regarded as normal. All of the CEM images observed from the surface to the deeper layers were concordant histopathologically with the biopsy results. Furthermore, CEM allowed observation of physiological functions such as blood flow in the capillaries of the surrounding crypts and mucus release from crypts. The immunohistochemical localization of fluorescein was consistent with the CEM images.

CEM provides endoscopists with a valuable new diagnostic tool, not only for observing tissue in situ at the histopathological level, but also for the coincident evaluation of physiological function during endoscopic examination.